gui: fix consumers_info coroutine usage + list-returning test mock + None-guard counts

- routes.py: change `async for ci in js.consumers_info(stream_name)` to
  `for ci in await js.consumers_info(stream_name)` — nats-py 2.14.0
  consumers_info() is a plain coroutine returning list[ConsumerInfo], not
  an async iterable; the old form threw TypeError silently (swallowed by
  except), causing every stream to show "unavailable" and zero consumers.
- test_consumers.py: replace async-generator mock with AsyncMock returning
  a list, matching the real API; also fix inline consumers_info_raising in
  the error test (remove dead yield); add explicit regression guard asserting
  consumer names appear in the template context.
- consumers_list.html: guard num_pending/num_ack_pending/num_redelivered/
  num_waiting with `… if … is not none else '—'` to prevent "None" in cells.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

src/central/gui/routes.py

@@ -2217,7 +2217,7 @@ async def consumers_list(request: Request) -> HTMLResponse:
 
         if js is not None:
             try:
-                async for ci in js.consumers_info(stream_name):
+                for ci in await js.consumers_info(stream_name):
                     consumers.append({
                         "name": ci.name,
                         "num_pending": ci.num_pending,

src/central/gui/templates/consumers_list.html

@@ -32,10 +32,10 @@ has no active subscriber — it is safe to delete if it is not a central-owned c
         {% for c in stream.consumers %}
             <tr>
                 <td style="padding: 0.25rem 0.5rem;">{{ c.name }}</td>
-                <td style="text-align: right; padding: 0.25rem 0.5rem;">{{ c.num_pending }}</td>
-                <td style="text-align: right; padding: 0.25rem 0.5rem;">{{ c.num_ack_pending }}</td>
-                <td style="text-align: right; padding: 0.25rem 0.5rem;">{{ c.num_redelivered }}</td>
-                <td style="text-align: right; padding: 0.25rem 0.5rem;">{{ c.num_waiting }}</td>
+                <td style="text-align: right; padding: 0.25rem 0.5rem;">{{ c.num_pending if c.num_pending is not none else '—' }}</td>
+                <td style="text-align: right; padding: 0.25rem 0.5rem;">{{ c.num_ack_pending if c.num_ack_pending is not none else '—' }}</td>
+                <td style="text-align: right; padding: 0.25rem 0.5rem;">{{ c.num_redelivered if c.num_redelivered is not none else '—' }}</td>
+                <td style="text-align: right; padding: 0.25rem 0.5rem;">{{ c.num_waiting if c.num_waiting is not none else '—' }}</td>
                 <td style="padding: 0.25rem 0.5rem;">{{ c.created.isoformat() if c.created else '—' }}</td>
                 <td style="text-align: center; padding: 0.25rem 0.5rem;">
                     {% if c.protected %}

tests/test_consumers.py

@@ -25,14 +25,11 @@ def _make_consumer_info(name: str, num_pending: int = 0, num_ack_pending: int =
 
 
 def _make_js_with_consumers(consumers_by_stream: dict):
-    """Build a mock JetStreamContext whose consumers_info is an async generator."""
+    """Build a mock JetStreamContext whose consumers_info is a coroutine returning a list."""
     mock_js = MagicMock()
-
-    async def consumers_info(stream_name):
-        for ci in consumers_by_stream.get(stream_name, []):
-            yield ci
-
-    mock_js.consumers_info = consumers_info
+    mock_js.consumers_info = AsyncMock(
+        side_effect=lambda stream, **kw: consumers_by_stream.get(stream, [])
+    )
     mock_js.consumer_info = AsyncMock()
     mock_js.delete_consumer = AsyncMock()
     return mock_js
@@ -108,6 +105,13 @@ class TestConsumersListWithConsumers:
         assert meshai_c["num_pending"] == 1000
         assert meshai_c["num_waiting"] == 0
 
+        # Regression guard: consumer names must appear in the template context so
+        # they are rendered into the HTML body (guards against the coroutine/iterator
+        # bug where consumers_info was consumed as an async-iterable instead of awaited).
+        consumer_names_in_context = {c["name"] for c in wx["consumers"]}
+        assert "archive-CENTRAL_WX" in consumer_names_in_context
+        assert "meshai-wx" in consumer_names_in_context
+
     @pytest.mark.asyncio
     async def test_stream_with_no_consumers_shows_empty(self):
         from central.gui.routes import consumers_list
@@ -147,9 +151,8 @@ class TestConsumersListWithConsumers:
         async def consumers_info_raising(stream_name):
             if stream_name == "CENTRAL_FIRE":
                 raise RuntimeError("stream not found")
-            # other streams: empty
-            return
-            yield  # make it an async generator
+            # other streams: empty list (coroutine returning a list, not an async generator)
+            return []
 
         mock_js.consumers_info = consumers_info_raising